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We present a deep Hubble Space Telescope (HST) imaging study of two dwarfgalaxies in the halos of Local Volume Large Magellanic Cloud (LMC) analogs.These dwarfs were discovered as part of our Subaru+Hyper Suprime-Cam MADCASHsurvey: MADCASH-1, which is a satellite of NGC 2403 (D~3.2 Mpc), and MADCASH-2,a previously unknown dwarf galaxy near NGC 4214 (D~3.0 Mpc). Our HST data reach>3.5 mag below the tip of the red giant branch (TRGB) of each dwarf, allowingus to derive their structural parameters and assess their stellar populations.We measure TRGB distances ($D=3.41^{+0.24}_{-0.23}$ Mpc for MADCASH-1, and$D=3.00^{+0.13}_{-0.15}$ Mpc for MADCASH-2), and confirm their associationswith their host galaxies. MADCASH-1 is a predominantly old, metal-poor stellarsystem (age ~13.5 Gyr, [M/H] ~ -2.0), similar to many Local Group dwarfs.Modelling of MADCASH-2's CMD suggests that it contains mostly ancient,metal-poor stars (age ~13.5 Gyr, [M/H] ~ -2.0), but that ~10% of its stellarmass was formed 1.1--1.5 Gyr ago, and ~1% was formed 400--500 Myr ago. Givenits recent star formation, we search MADCASH-2 for neutral hydrogen using theGreen Bank Telescope, but find no emission and estimate an upper limit on theHI mass of $<4.8\times10^4 M_{\odot}$. These are the faintest dwarf satellitesknown around host galaxies of LMC mass outside the Local Group($M_{V,\text{MADCASH-1}}=-7.81\pm0.18$, $M_{V,\text{MADCASH-2}}=-9.15\pm0.12$),and one of them shows signs of recent environmental quenching by its host. Oncethe MADCASH survey for faint dwarf satellites is complete, our census willenable us to test CDM predictions for hierarchical structure formation, anddiscover the physical mechanisms by which low-mass hosts influence theevolution of their satellites.

Hubble Space Telescope Observations of Two Faint Dwarf Satellites of Nearby LMC Analogs from MADCASH